Technical Field
This application is directed to detection of an output power-maximizing duty cycle of a boost converter and in particular to a boost converter having a feedback stage that generates the duty cycle and operates the boost converter in accordance with the duty cycle.
Description of the Related Art
Boost converters are conventionally operated at a variable duty cycle with a fixed maximal value. Limiting the boost converter to the maximal duty cycle protects the boost converter against excessive inductor current, but does not maximize the output power provided by the boost converter. For example, as the input available (maximal) power provided by a voltage source, such as a battery, decreases over time and with use, the output power of the boost converter is intended to be constant by a feedback regulation loop. However, with the duty cycle limited to a maximal value, DMAX, the boost converter does not reach desired output voltage, and thus the output power. Furthermore, operating the boost converter without a fixed (or with a high value) duty cycle limit introduces a risk of destabilizing the boost converter. By exceeding some critical duty cycle value, DCRIT, the boost converter is destabilized and comes to fall in a negative gain region of the boost converter input-output conversion characteristic.